Comment header() in Session.php

extension/Classes/Core/Store/Session.php

@@ -82,7 +82,8 @@ class Session
             // Currently, setcookie() is only called to really extend the lifetime. All other parameter needs to be given again.
             // For PHP Version < 7.3 cookie with samesite can only be set over the header() method.
             if(PHP_VERSION_ID < 70300) {
-                header("Set-Cookie: ".SESSION_NAME."=".session_id()."; expires=".$date."; path=".$path."; domain=".$currentCookieParams['domain']."; HttpOnly; SameSite=Lax");
+// header() here makes no senss, cause it's to late: T3 already sent some non header content.
+//                header("Set-Cookie: ".SESSION_NAME."=".session_id()."; expires=".$date."; path=".$path."; domain=".$currentCookieParams['domain']."; HttpOnly; SameSite=Lax");
             } else {
                 setcookie(SESSION_NAME, session_id(), [
                     'expires' => time() + $lifetime,